isFibonacci method

bool isFibonacci()

Checks if this integer is a Fibonacci number.

Implementation

bool isFibonacci() {
  final n1 = 5 * this * this + 4;
  final n2 = 5 * this * this - 4;
  return NumbersHelper.isPerfectSquare(n1) ||
      NumbersHelper.isPerfectSquare(n2);
}